The increasing demand for data and other services over the Internet and other networks has placed increasing demands on network access nodes, such as Internet service providers (ISPs) and other signal transfer points. One type of emerging data facility is broadband Internet over cable modems. Networks servicing broadband cable links may include both coaxial copper links as well as optical fiber connections, typically interfaced using optical/electrical or electrical/optical (O/E or E/O) converters. In recent times, the relatively high bandwidth offered by coaxial cable or hybrid fiber/cable networks has permitted the delivery of traditional Internet, telephony, video and other services at data rates of up to one Megabit/sec and more, making such facilities attractive for consumers, businesses and others with more intensive data needs.
When access to the Internet or other networks is provided by way of a cable modem site, the intake feeds from fiber, cable or other links is often terminated in a cable modem termination system (CMTS), as for instance illustrated in FIG. 1. The CMTS may contain a set of radio frequency (RF) receivers to which individual data feeds may be routed for decoding. However, CMTS equipment such as that installed in cable TV, headend or other network facilities may on occasion fail.
To protect against that case, a CMTS 102 as illustrated in FIG. 1 may be connected to a backup CMTS 106, via a switch 104. The switch 104 may be configured to monitor the CMTS 102 to detect power failures, software faults or other fault conditions and transfer the delivery of incoming RF or other signal to the backup CMTS 106, so that subscribers to Internet service, video service, telephony or other data services may be diverted through the backup equipment to the Internet or other network without substantial interruption.
However, in commercial practice the switch 104 has been implemented as a mechanical switch or relay, whose dependability may itself not be guaranteed. Therefore, in conventional failover mechanisms in cable modem installations, it is possible for data customers to experience complete access failure and significant network downtime.
Moreover, as illustrated in FIG. 2, the network wiring for broadband deployment in cable TV headends can become complicated, cumbersome and expensive. In a cable TV node as illustrated in FIG. 2, individual households or other sites having a cable TV, modem or other broadband access device may each feed and receive signals to and from an optical/electrical converter 110, such as homes in a neighborhood or businesses on a campus or street. The optical/electrical converter 110 may translate the signals from optical to electrical format as appropriate, and communicate those signals to a cable TV headend 108, directly or via a block converter 112, splitter or other resources.
A block converter 112 may aggregate multiple customer data links on to one backbone communications link for delivery to a cable TV headend 108. The block converter 112 may do so by allocating frequencies within a frequency space to each of the customer data signals, and therefore make efficient use of available physical plant and bandwidth to the cable TV headend 108.
After receipt by one or more optical/electrical converter 110, the signals may be delivered to individual RF receivers within the CMTS 102. However, and as illustrated in FIG. 2, each of the one or more optical/electrical converter 110 must feed a corresponding receiver, meaning that within the cable TV headend 108 a large number of cables are required to mate cables and receivers, any of which could fail, become shorted or otherwise malfunction. Significant heat may be generated from the wiring nest, and repair may be difficult since functioning wires must not be disturbed.
In addition, in this type of conventional cable TV headend 108, the CMTS may be backed up by a backup CMTS 106 via switch 104, which again is implemented as a relay or other mechanical switching fabric prone to mechanical disturbance, and which requires some amount of time to effect the switching action. Reliability, convenience, installation footprint and other aspects of the broadband facility could be enhanced by more advanced headend equipment. Other problems exist.